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(No Model.) 3 Sheets-Sheet 1 W. B. P. ELPHINSTONE & O. W. VINCENT. DYNAMO ELEGTRIG MACHINE.

No. 288,042. Patented Nov. 6, 1883.

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DYNAMO ELECTRIC MAUHINE. No. 288.042. Patented Nov. 6, 1883.

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DYNAMO ELEGTRIG MACHINE.

Patented Nov. 6. 1883.

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.. 9 12 fl t-5 UNITED STATES PATENT OFFIC VILLIAM B. F. ELPHINSTONE, OF GARBERRY TOVER, MUSSELBURGH, SCOT- LAND, AND CHARLES IV. VINCENT, OF HOLLOIVAY, COUNTY OF MIDDLF- snx, ENGLAND.

DYNAMO-ELECTRIC MACHINE.

SPECZFICATION forming part of Letters Patent No. 288,042, dated November 6, 1883.

Application filed November 17, 1882. (No model.)

I [all whom it may concern/.-

Be it known that we, WILLIAM BULLER FULLERTON ELPI-IINSTONE, (Baron Elphinstone,) of Carberry Tower, Musselburgh, Scotland, and CHARLES WILsONVINoENT, of H01- loway, in the county of Middlesex, England, have invented new and useful Improvements in Dynamo-Electric Machines, of which the following is a specification.

The object of this invention is so to arrange dynamo-electric machines that under greatlyvarying circumstances they will admit of being worked economically as respects the power used to impart rotary motion thereto. Ve I 5 have found, in working our dynamo-electric machine for which we obtained British patents dated, respectively, January 27, 1879, and July 13, 1880, that when the maximum amount of work which it is calculated to perform is put upon it in the external circuit the greatest economy in respect of the expenditure of power is observable. This is due to the small percentage of internal resistance which exists in comparison with the external resistance.

2 On reducing the amount of work in the external circuit the proportion of the total power employed in overcoming the internal resistance of the machine was increased, and this in the reverse proportion to the reduc- 0 tion of the eiiieient work performed. This effect is due to the internal resistance of the machine being a constant quantity, although the etficient work outside is caused to vary. \Vith the object of securing economical working, dynamo-machines have' hitherto been constructcd specially for the work required to be performed, the prevalent belief being that to secure this result it was necessary to work them near or up to their highest capacity. In

0 order, however, to render these machines,

like motive-power engines, capable of working economically under varying circumstancesfor example, to maintain indiiferently lamps connected in series or single parallels,

5 or one hundred or fivehundred lamps ina se ries, in single groups or parallels, as ClICllIIlstances may rcquirewe propose to divide up the field and send separate and distinct currents through groups of coils, or through each coil, as circumstances may require, in place of connecting all the coils of the field-magnets together, as heretofore, whereby one unalterable course 10f the exeiting current was provided, and by this means to modify the resistance so as to suit the work in hand. For this purpose we bring the terminals of each coil of the fieldmagnets to a grouping-tablet, to which, also, we connect the ends of the wires that serve to convey the excitingcurrent to the field.

In the accompanying drawings we have shown in side elevation at Figure 1, in crosssection at Fig. 2, and in longitudinal section at Fig. 3 our dynamo-electrical machine so modified as to secure thereby the abovc-mentioned results. Figs. 4, 5, and 6 are diagrams of grouping-tablet and circuits.

A A are cast-iron standards bolted to abedplate, A, also of cast-iron. Mounted in these standards A A is a fixed axle, B, on which is mounted loosely an armature-drum, G, carrying on its periphery coils or hanks of insulated wire, the ends of which coils are led down to a commutator, D. Situate within the drum, and fitted to the fixed axle B, are six radial arms, E, coiled with insulated wire, so as to constitute them six electro-magnets. Corresponding with these electro-magnets E are six external ,electro-magnets, F, which form,with the internal magnets, fields of force which the hanks carried by the armaturedrum are in its rotation caused to cut. The ends of each coil of the external and internal field-magnets are led to a grouping-tablet, G, situate, for convenience, in front of one of the standards A, the use of which will be presently explained.

The commutator D maybe supposed to rep resent a double commutator, the armature being furnished with two sets of coils, the termio nals of one set going to one part of the commutator and the terminals of the other set of coils going to the other part of the commutator. \Vhen this arrangement is adopted,two sets of brushes or rubbers, H H, are required, 5 the one set, H, serving to feed the field, and the other set, H, to collect and transmit the currents to the lamps or other work in hand.

These brushes are carried by an adjustable ring, I, which is supported by standards on the bed-plate of the machine.

J is a driving-pulley on the hub of the armature-drum, and through it rotary motion is communicated to the drum by a band from a prime mover;

We will nowprocced to explain in detail.

how the results which ,our invention is intended to secure are obtained.

It has been stated that the terminals of the coils of the several field-magnets are connected with a grouping-tablet, G. This is illustrated 4 in the diagram Fig. 4, where the outer fieldl magnets are marked with the letters a b 0d cf and the inner field-magnets e 11* 0 (1 e f 1 The groupingtablet may be described as consisting of a slab of insulating material, and

have indicated by giving to them similar letters of reference, distinguishing by numbers which pole of each magnet is connected with i Thus the pole 1 of the magnet a will be connected with the plate a,

its respective plate.

and the pole 2 of the same magnet will be connected with the plate a two series.

three sides by an insulated brass strip, 9'. This strip is connected by a wire with one of the brushes h, and the insulated strip 9 is lie parallel thereto.

similarly connected with the other brush, h.

Thus, whenthe machine is set to work, the induced exciting-current intended for the field will be conducted to the grouping-tablet G,

whence it may be delivered to the field-magf net coils in the order best suited for the work in hand. V

The diagram Fig. 4 shows a number of holes made'in the insulating-slab between the pairs of plates and the strips 9 and g, which 1 These holes are intended 1 to receive metal plugs, to establish metallic contact where desired. Supposing, now, it is required to obtain a current of maximum intensity, we couple up the magnet-coils, as indicated in the diagram Fig. 4, where the white spots indicate the inserted plugs, the black spots serving to show the vacant holes. the plates and strips are put into metallic communication, as in Fig. 4, the course of the current will be as follows: The current, entering I by thestrip y, will pass to the plate a thence through the coil of the magnet a, and back to "the plate a. From this plate it will pass to the plate b, thence around the magnet 12, back tend past the plate a The connection of l Similarly the pole l 1 of the magnet a is connected with the plate .1 e and the pole 2 o'fthe magnet e is connected with the plate a, and so on throughout the These series of plates, all insulated the one from the other, are divided 'bya brass strip, g, and they are surrounded onby the contact-plug to the plate 0 around the 7 magnet 0, back to the plate 0, and so on through the series of plates and magnet-coils until the current reaches the last plate of the outside series, f which plate is made L-shaped to exeral extension of the-plate a of the inner series of electro-magnets, and being coupled to that plate by a metallic plug, the current passes to that plate, and thence through the coil of the electro-magnet a From this magnet the current passes to the plate a and thence in consecutive order through the coils of all the internal magnets until it passes from the coil of the magnet f X to the plate f As this plate is connected by a metallic plug with the strip 9, the current will pass to that strip, and thence through the wire which connects it with a brush, h, thus completing the circuit. This mode ofcou-pling'up permits of the excitingcurrent passing in the ordinary manner through the field, and is effective for insuring the full efllciency of the machine when the maximum resistance inthe fieldmiagnets is required. Supposing, now, it is desired to reduce the resistance in the field-magnets to meet a varied condition of the work to be performed, we couple up our metallic plates and strips, as illustrated at diagram Fig. '5, where it will be seen that each pair of plates is in'dire'ct communication with the strips 9 andg'. Thus the current, entering at y will pass simultaneously by the plates bc d c f a to their Here it reaches a let respective magnets, thence back to the plates a b c" d ev f 2 to the strip 9, and so to the brush, by which'the circuit is completed. Similarly the current from the strip 9 will be divided I up among the plates a to f of the inner field-magnets. By thus coupling up the terminals on thegroupingtablet G, the resistance of the field-magnets will be reduced to a minimum, and the motive force employed 'for driving the machine will be proportionately efiiciently employedin producing currents for ex ternal work. A further and most important advantage consequent on this mode of reducl ing the resistance is that when half or threefourths of the number of lamps in a circuit are thrown out of use the ratio of the internal resistan'ce of the machine to the work performed will remain unaltered, and consequently the motive power required to drive the machine may be reduced as the external work of the machine is reduced.

The diagram Fig. 6 illustrates a mode of coupling whereby the exciting-current is sent through the group of external magnets in series and through the group of internal magnets in series. Thus the resistance is very greatly increased as compared with Diagram 5 and is reduced to one-fourth as compared IIO with Diagram 4. Comparing Diagram 6 with siderably increased.

couples the plate f with the plate a, and I connecting these two plates by metallic plugs, the one, (0, with the strip 9, and the other, f with the strip 9.

The brushes H may conveniently be connected with a grouping-tablet such asthat shown at K, Fig. 4, which, being provided with plugs, will facilitate the coupling up of the brush-wires for intensity or quantity to suit the work in hand.

In explaining our invention we have referred to a machine in which the excitingcurrent is obtained from a special series of coils or hanks on the armature. Ve may, however, obtain the exciting-current from one of the main circuits, or from a shunt in the well-known manner, or from a source distinct from the machine to be excited; but the current, however derived, will be conducted to the grouping-tablet G, or its equivalent, and distributed through the magnetic field, in the manner above explained, to suit the work in hand.

From the foregoing it will be understood that the application of the invention is not limited to the form of dynamo-electric machine shown in the drawings, but may be ap plied wherever the field contains two or more magnets.

Having now set forth the nature of our invention, we may remark that we are aware that it has been proposed to arrange in dynamo-electric machines furnished with compound tubular elcctro-magnets the wires of the coils so that they may, at the option of the attendant, be changed from intensity to quantity or from quantity to intensity; but dynamo-machines thus constructed admit of only these two changes, and present this further disadvantage that whatever change is made in the resistance in the coils of the field-magnets is made also in the outside or working circuits, and these circuits are broken when ever such changes are made. Besides these disadvantages, the cost of construction is con By our arrangement, however, not only is the cost of constructing the field-magnets unaffected, but we are euabled to make a great variety of changes in the producing power of our machine from a minimum, consequent on charging one of the field-magnets only, to a maximum, consequent on charging the whole of the field-magnets in quantity. Between these two points we can effect any change of combination rapidly and without breaking or otherwise interfering with the outside or working circuit or circuits; and we can therefore adjust the amount of electromotive force, so as to exactly meet the requirements of the lamps or other work in hand.

\Ve therefore claim as our invention and desire to secure by Letters Patent 1. The combination, with the source of the exciting-current for the field -n1agnets of a dynamo-electric machine, of a grouping-tab let or its equivalent in electrical connection with said source, and independent of the main circuit, and in which the coils of the several field-magnets have their terminals, such terminals being so arranged as to admit of their being connected singly with the source of supply, or coupled up in series or groups for the purpose of adjusting theresistance of the fieldmagnets to suit the work in hand, substantially as herein described.

2. In a dynamo-electric machine, the combination of the field or fields of separate magnets or magnets wound with distinct wires and independent of the main circuit, and a groupin g-tablet or its equivalent, providing for the exciting current being passed around said magnets singly or in groups directly from a common source, without affecting the outside circuit, substantially as described.

ELPHINSTONE. CHAS. XV. VINCENT. lVitucsscs to the signature of \Villiam Buller Fullerton Elphinstone, (Baron Elphinstonez) J osnrrr BARFORD,

C(u'berry Tower, illiraadburglz, Scotland. H. K. XVHITE,

Chancery Lane, London. \Vitncsses to the signature of Charles Vilson Vincent:

H. K. WHITE, Gno. Grrn'rrn,

B0171 of Chmzccry Lane, London. 

